Patent Document 1 discloses a control device for a variable valve timing mechanism configured to change the camshaft phase by adjusting the rotation speed of a motor relative to half the rotation speed of the crankshaft. The control device includes: a means for calculating an actual valve timing based on the cam angle signal and crank angle signal upon each output of the cam angle signal; a means for calculating an amount of valve timing change at a predetermined calculation frequency based on a difference between the rotation speed of the motor and half the rotation speed of the crankshaft; and a means for calculating a final actual valve timing based on the calculated actual valve timing at the output of the cam angle signal and the calculated amount of valve timing change.